Related-art induction heating cookers include ones that determine the temperature of the heating target based on an input current or a controlled variable of an inverter (see, for example, Patent Literatures 1 and 2). The induction heating cooker described in Patent Literature 1 includes the control means for controlling the inverter so that the input current of the inverter becomes constant, and in a case where the controlled variable changes by the predetermined amount or more in the predetermined period of time, it is determined that the change in temperature of the heating target is large to suppress the output of the inverter. It is also disclosed that, in a case where the change in controlled variable becomes the predetermined amount or less in the predetermined period of time, it is determined that water boiling has finished, and the driving frequency is reduced to reduce the output of the inverter.
Patent Literature 2 proposes the induction heating cooker including input current change detecting means for detecting the amount of change in input current, and temperature determination processing means for determining the temperature of the heating target based on the amount of change in input current, which is detected by the input current change detecting means. It is also disclosed that, in a case where the temperature determination processing means determines that the heating target has reached the boiling temperature, the stop signal is output to stop heating.
Further, in an induction heating cooker, in order to prevent heating an empty heating target, it has been proposed to detect an input current to an inverter circuit, and stop or reduce an output of the inverter circuit when a change with time of the detected input current exceeds a preset value (see, for example, Patent Literature 3).